This work describes the surface modification of filter paper by a photoinduced grafting process involving a poly(oxetane) acrylic oligomer with short perfluoroalkyl chains. This modifier avoids the safety, environmental and health concerns of conventional long perfluoroalkyl-chain chemistries, without sacrificing their key performance features. Therefore the work provides an alternative to existing processes aiming to make the paper hydrophobic: the chemicals used are safe, the proposed functionalization process is rather simple and inexpensive, moreover can be adapted to paper making plants.
The experiments show that the grafting induced by UV irradiation changes the surface composition of the samples as assessed by surface spectroscopies and other measurements. As a result of the surface modification, water contact angles on treated paper surfaces were as high as 143° approaching superhydrophobicity. Also oleophobicity was improved (ϑ = 57°), guaranteeing grease and antistain resistance. Surface tension was strongly reduced and water resistance was improved. XPS, static and dynamic contact angles and capillary wetting studies indicate a substantial gradient in surface energy normal to the treated paper surface.
► UV-induced grafting of cellulose is a successful strategy for paper modification ► A short (C2F5) perfluoroalkyl chain acrylate was grafted on filter paper ► Its surface composition was changed as assessed by surface spectroscopies ► Quasi superhydrophobicity and oleophobicity was imparted to paper ► Grease resistance and water resistance of paper were improved.
Figures and tables from this article:
|Sample||PI (wt% vs monomer)||Monomer (g/L)||Irradiation time (min)||θ water (°)||θ hexadecane (°)|
Iflux = 25 mW/cm2.
|Sample||Irradiation time (min)||Monomer (g/L)||PI (wt% vs monomer)||Gas atmosphere||
Capillary wetting contact angle
||Dynamic contact anglee||Static contact anglef|
|θHexadecane (°)||θWater (°)||θWater (°)||θWater (°)|
|1a and b||–||–||–||–||0||69.3 ± 0.7||–d||–|
|5Ab||2||4||0||N2||46.0 ± 5||43.4 ± 31||119.7||118|
|2Ab||2||4||1.5||N2||8.83 ± 15||68.2 ± 9||117.9||122|
|9c||2||4||1.5||N2||35.8 ± 14||71.9 ± 30||112.4||117|
|7Ab||2||1||0||N2||46.8 ± 7||66.4 ± 6||109.8||114|
|8b||2||4||1.5||Air||34.8 ± 8||74.7 ± 13||92.94||118|
Iflux = 51 mW/cm2.
Iflux = 25 mW/cm2.
Too rapid to measure.
After application of Wenzel correction.
|Sample||Monomer (g/L)||PI (wt% vs monomer)||Gas atmosphere||
|Sample||Monomer (g/L)||PI (wt% vs monomer)||Gas atmosphere||Mole faction of monomer at paper surface||Molecules of monomer/ten glucosidic units|
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